Is there oil in the dampers?

I don't think this alone would account for what you're experiencing, but they sure don't run well without oil.

Ideally, I'd recommend taking the carbs apart and giving everything a good cleaning with a nonabrasive solvent, the putting it all back together. If that's more than you can take on just now, you could just remove the pistons and needles, then irrigate the jet with some carb cleaner. This is a pretty halfassed approach but might loosen up the varnish enough to get it to behave.

You'll still want to give them a good cleaning when you have the chance, though.

Good luck!

Cameron
Portland